Valves, valved fluid transfer devices and ambulatory infusion devices including the same

ABSTRACT

Valves, valved fluid transfer devices and ambulatory infusion devices including the same. The valves includes a valve element and a valve seat, and one of the valve seat and the valve element includes a main portion and a seal portion that is less tacky than the main portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Ser.No. 60/896,910, filed Mar. 24, 2007 and entitled “Valves, Valved FluidTransfer Devices and Ambulatory Infusion Devices Including The Same,”which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTIONS

1. Field of Inventions

The present inventions relate generally to valve seats, valves, valvedfluid transfer devices and ambulatory infusion devices including thesame.

2. Description of the Related Art

Ambulatory infusion devices, such as implantable infusion devices andexternally carried infusion devices, have been used to provide a patientwith a medication or other substance (collectively “infusiblesubstance”) and frequently include a reservoir and a fluid transferdevice. The reservoir is used to store the infusible substance and iscoupled to the fluid transfer device which is, in turn, connected to anoutlet port. A catheter, which has at least one outlet at the targetbody region, may be connected to the outlet port. As such, infusiblesubstance in the reservoir may be transferred from the reservoir to thetarget body region by way of the fluid transfer device and catheter.

The fluid transfer devices in ambulatory infusion devices frequentlyinclude a pump, such as an electromagnet pump, and one or more valves.The present inventors have determined that the valves employed in suchfluid transfer devices are susceptible to improvement. For example, thepresent inventors have determined that the main check valves aresusceptible to improvement. Main check valves typically include a valveseat and a valve element that is movable relative to the valve seat. Thevalve element moves between a closed position where the valve elementengages and compresses the valve seat, and an open position where thevalve element is spaced from the valve seat. The present inventors havedetermined that adhesion of the valve element to the valve seat,including an increase in adhesion over time in normally closed valves,can reduce the effectiveness of the fluid transfer device by increasingthe threshold force required to open the valve. Increasing the thresholdforce required to open the valve will, in turn, increase the load on thebattery and may reduce the amount of fluid that flows through the valveduring each pump cycle. The adhesion may also reduce the life of thevalve seat itself. The present inventors have also determined thatadhesion, including an increase in adhesion over time in normally closedvalves, can reduce the effectiveness of other types of valves that maybe associated with implantable infusion devices (e.g. bypass valves,outlet valves, pressure regulator valves, fill port valves, valves thatemploy a reference pressure, header assembly valves, and valves that areassociated with catheters).

BRIEF DESCRIPTION OF THE DRAWINGS

Detailed descriptions of exemplary embodiments will be made withreference to the accompanying drawings.

FIG. 1 is a side, partial section view of a fluid transfer device inaccordance with various embodiments of some of the present invention.

FIGS. 2-5 are section views showing the fluid transfer deviceillustrated in FIG. 1 in various states.

FIG. 6 is a plan view of a valve seat in accordance with one embodimentof a present invention.

FIG. 7 is a section view taken along line 7-7 in FIG. 6.

FIG. 8 is a plan view of a valve seat in accordance with one embodimentof a present invention.

FIG. 9 is a section view taken along line 9-9 in FIG. 8.

FIG. 10 is a plan view of a valve seat in accordance with one embodimentof a present invention.

FIG. 11 is a section view taken along line 11-11 in FIG. 10.

FIG. 12 is a plan view of a valve seat in accordance with one embodimentof a present invention.

FIG. 13 is a section view taken along line 13-13 in FIG. 12.

FIG. 14 is a plan view of a valve seat in accordance with one embodimentof a present invention.

FIG. 15 is a section view taken along line 15-15 in FIG. 14.

FIG. 16 is a plan view of a valve seat in accordance with one embodimentof a present invention.

FIG. 17 is a section view taken along line 17-17 in FIG. 16.

FIG. 18 is section view of a portion of a valve in accordance with oneembodiment of a present invention.

FIG. 19 is section view of a portion of a valve in accordance with oneembodiment of a present invention.

FIG. 20 is a block diagram of a fluid transfer device.

FIG. 21 is a plan view of an implantable infusion device in accordancewith one embodiment of a present invention.

FIG. 22 is a plan view of the implantable infusion device illustrated inFIG. 20 with the cover removed.

FIG. 23 is a partial section view taken along line 23-23 in FIG. 21.

FIG. 24 is a block diagram of the implantable infusion deviceillustrated in FIGS. 21-23.

FIG. 25 is a section view of a bypass valve in accordance with oneembodiment of a present invention.

FIG. 26 is a section view of an outlet valve in accordance with oneembodiment of a present invention.

FIG. 27 is a partial section view of a pressure regulator in accordancewith one embodiment of a present invention.

FIG. 28 is a partial section view of a fill port in accordance with oneembodiment of a present invention.

FIG. 29 is a partial section view of a fill port in accordance with oneembodiment of a present invention.

FIG. 30 is a partial section view of a fill port in accordance with oneembodiment of a present invention.

FIG. 31 is a section view of a pressure control valve in accordance withone embodiment of a present invention.

FIG. 32 is a section view of a portion of a pressure control valve inaccordance with one embodiment of a present invention.

FIG. 33 is a section view of a portion of a pressure control valve inaccordance with one embodiment of a present invention.

FIG. 34 is a partial section view of a pressure control valve inaccordance with one embodiment of a present invention.

FIG. 35 is a section view of a portion of a pressure control valve inaccordance with one embodiment of a present invention.

FIG. 36 is a plan view of an implantable infusion device in accordancewith one embodiment of a present invention.

FIG. 37 is a partial section view of a portion of a catheter assembly inaccordance with one embodiment of a present invention.

FIG. 38 is a plan view of a catheter assembly in accordance with oneembodiment of a present invention.

FIG. 39 is a plan view of a catheter assembly in accordance with oneembodiment of a present invention.

FIG. 40 is a plan view of an implantable infusion device in accordancewith one embodiment of a present invention.

FIG. 41 is a schematic view of the implantable infusion deviceillustrated in FIG. 40.

FIG. 42 is a partial section view of a valve in accordance with oneembodiment of a present invention.

FIG. 43 is a partial section view of a portion of a valve in accordancewith one embodiment of a present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The following is a detailed description of the best presently knownmodes of carrying out the inventions. This description is not to betaken in a limiting sense, but is made merely for the purpose ofillustrating the general principles of the inventions. The presentinventions have application in a wide variety of apparatus. One exampleis an electromagnet-pump-based fluid transfer device that may beemployed in an implantable infusion device, and some of the presentinventions are discussed in the context of electromagnet-pump-basedfluid transfer devices and implantable infusion devices. The presentinventions are not, however, limited to electromagnet-pump-based fluidtransfer devices and implantable infusion devices and are instead alsoapplicable to other fluid transfer devices and infusion devices thatcurrently exist, or are yet to be developed. For example, the presentinventions are applicable to fluid transfer devices with solenoid pumps,piezoelectric pumps, and any other mechanical or electromechanicalpulsatile pump, as well as to externally carried infusion devices.

One example of a fluid transfer device is illustrated in FIGS. 1-5. Theexemplary fluid transfer device, which is generally represented byreference numeral 100, includes a housing 102, an electromagnet pump104, a bypass valve 106 and a main check valve 107. The valves 106 and107 are in fluidic communication with the pump 104. The housing 102 inthe exemplary fluid transfer device 100 is a generally solid,cylindrical structure with various open regions. The open regionsaccommodate portions of structures, such as the electromagnet pump 104,bypass valve 106, main check valve 107, and also define a fluid flowpath. More specifically, the housing 102 includes a piston bore 108 anda hub recess 110 that respectively receive the electromagnet pumparmature piston 146 and armature hub 148 (discussed below). A weld ring112, which is secured to the end of the housing 102 opposite the maincheck valve 107, defines a pole recess 114 for the armature pole 144(discussed below). A pair of valve recesses 116 and 118 for the bypassvalve 106 and main check valve 107 are also provided. With respect tothe fluid flow path, the housing 102 includes an orifice 120 thatextends from the piston bore 108 to the bypass valve recess 116, abypass fluid chamber 122, fluid passages 124 and 126, and an outletrecess 128. Additionally, and although it is not limited to anyparticular material(s), the exemplary housing 102 is formed fromtitanium.

Turning to the pump portion of the exemplary fluid transfer device 100,the electromagnet pump 104 includes an electromagnet 130 and an armature132. The electromagnet 130, which is carried within in a case 134,includes a core 136 and a coil 138. The case 134 and core 136 are madefrom a magnetic material. The coil 138 consists of a wire or otherconductor that is wound around the core 136. The coil 138 may beinsulated from the case 134 by electrically non-conductive spacers (notshown), which center the coil within the case, or through the use ofpotting compound or encapsulant material between the case and the coil.

The electromagnet case 134 is secured to the housing 102 in theexemplary fluid transfer device 100 through the use of theaforementioned weld ring 112 on the housing and a weld ring 140 on thecase. More specifically, the outer diameters of the weld rings 112 and140 are substantially equal to one another and the outer surfacesthereof are substantially flush. During assembly, the housing 102 andthe electromagnet case 134 are positioned on opposite sides of a barrier142 and are then secured to one another by a weld (not shown) joiningthe outer surfaces of the weld rings 112 and 140. The barrier separatesthe pole recess 114, which will ultimately be filled with fluid, fromthe electromagnet 130.

The armature 132 in the illustrated embodiment is positioned within afluid containing region of the housing that is defined by the pistonbore 108, the hub recess 110 and the pole recess 114. The exemplaryarmature 132 consists of a pole 144 formed from a magnetic material(e.g. magnetic steel), which is located within the pole recess 114 suchthat it will be magnetically attracted to the electromagnet 130 when theelectromagnet is actuated, and a cylindrically-shaped piston 146 thatextends from the pole and through the piston bore 108 to the main checkvalve 107. A hub 148 is located within the hub recess 110 and is used tosecure the pole 144 to the piston 146. A main spring 150 biases thearmature 132 to the “rest” position illustrated in FIG. 1. The mainspring 150 is compressed between a spring retainer 152 on the hub 148and a spring retainer plate 154. The spring retainer plate 154, which isheld in place by the housing 102 and the weld ring 112, includes aninlet opening 156 that allows fluid to pass from the fluid passage 124to the pole recess 114 and an outlet opening 158 that allows fluid topass from the pole recess to the fluid passage 126.

Turning to FIG. 2, the main check valve 107 includes a housing 160,which may be positioned within the valve recess 118 and secured to thehousing 102, and a valve element (or “plunger”) 162 that is movablerelative to the housing 160. The exemplary housing 160 has a generallycylindrical fluid flow portion 163, with a fluid lumen 164 that isopened and closed by the valve element 162, and a mounting portion 165that is used to secure the main check valve 107 to a fluid transferdevice or other structure. In the illustrated embodiment, which isconfigured for use with a cylindrical fluid transfer device, themounting portion 165 is disk-shaped. In other embodiments, the mountingportion 165 may be resized, reshaped or omitted altogether. The valveelement 162 includes an end portion, such as the illustrated head 166,that abuts an elastomeric valve seat 168 when the main check valve 107is in the closed state illustrated in FIG. 2. The shaft portion of thevalve element 162 passes through an opening 169 in the valve seat 168.The valve element 162 is biased to the closed position by a spring 170(e.g. a coil spring) or other suitable biasing device. One end of thespring 170 abuts the housing 160 and the other end abuts a springretainer 172 that is secured to the valve element 162. The exemplaryvalve seat 168, and other exemplary valve seats, are discussed ingreater detail below in the context of FIGS. 6 and 19.

With respect to manufacturing and materials, the housing 160 in theexemplary main check valve 107 is a machined part and suitable materialsfor the housing include, but are not limited to, titanium, titaniumalloys, stainless steel (e.g. 316L stainless steel), cobalt-nickelalloys, and refractory metals such as tantalum. The valve element 162may also be machined and suitable materials for the machined valveelement include, but are not limited to, those described above in thecontext of the housing 160. Alternatively, the valve element 162 may bemolded and suitable materials for a molded valve element include, butare not limited to, polyolefins, liquid crystal polymers, PEEK,polyacetal plastics such as Delrin®, fluoropolymers, and most othermolded materials that are rigid and inert to pharmaceuticals.

With respect to the bypass valve, the exemplary bypass valve 106illustrated in FIG. 2 includes a valve element 174 with an integralsealing ring 176. The sealing ring 176, which has a semi-circularcross-sectional shape, engages the wall (or “seat”) 178 that defines theend of the valve recess 116 and surrounds the orifice 120 when in theclosed position illustrated in FIG. 2. Otherwise identical valveelements without the sealing ring may also be employed in the bypassvalve. Suitable materials for the valve element 174 include elastomerssuch as, for example, silicone rubber, latex rubber, fluoropolymers,urethane, butyl rubber, and isoprene. In other implementations, thevalve element 174 may be formed in whole or in part from a metal. Thevalve element 174 is biased to the closed position by a spring 180. Oneend of the spring 180 abuts the valve element 174, while the other endabuts a plug 182 that may be secured to housing 102 to maintain thebypass valve 106 within the valve recess 116. The plug 182 also forms afluid tight seal which prevents fluid from escaping from the housing 102by way of the valve recess 116.

Fluid may be supplied to the exemplary fluid transfer device 100illustrated in FIG. 1 by way of an inlet tube 184. To that end, andreferring to FIG. 2, the main check valve housing 160 includes a recess186, with a shoulder 188, that receives the inlet tube 184. A filter(not shown) may be positioned within the recess 186 between the inlettube 184 and the shoulder 188. The recess 186 and shoulder 188 may,alternatively, be associated with the fluid flow portion 163, or withboth the fluid flow portion and the mounting portion 165, in otherimplementations of the main check valve 107. Fluid exits the fluidtransfer device 100 by way of an outlet tube 190 (FIG. 1) that isreceived within the outlet recess 128 in the housing 102.

The exemplary fluid transfer device 100 operates as follows. Referringfirst to FIGS. 1 and 2, the fluid transfer device 100 is shown here inthe “rest” state. The armature 132 is in the rest position, theelectromagnet 130 is not energized, and the bypass valve 106 and maincheck valve 107 are both closed. Under normal operating conditions,there will be no flow through the fluid transfer device 100 when thefluid transfer device is in the rest state and the valves 106 and 107are closed. Although sufficient pressure at the inlet tube 184 couldresult in the flow through the fluid transfer device 100 while the fluidtransfer device is in the rest state illustrated in FIG. 2, thelikelihood that this could occur is greatly reduced by maintaining thefluid source at a relatively low pressure.

The exemplary fluid transfer device 100 is actuated by connecting thecoil 138 in the electromagnet 130 to an energy source (e.g. one or morecapacitors that are being fired). The resulting magnetic field isdirected through the core 136 and into, as well as through, the armaturepole 144. The armature pole 144 is attracted to the core 136 by themagnetic field. The intensity of the magnetic field grows as currentcontinues to flow through the coil 138. When the intensity reaches alevel sufficient to overcome the biasing force of the main spring 150,the armature 132 will be pulled rapidly in the direction of arrow A(FIG. 2) until the armature pole 144 reaches the barrier 142. Thearmature piston 146 and hub 148 will move with armature pole 144 andcompress the main spring 150. This is also the time at which fluid exitsthe fluid transfer device 100 by way of the passage 126 and the outlettube 190.

Movement of the armature piston 146 from the position illustrated inFIG. 2 to the position illustrated in FIG. 3 results in a decrease inpressure in the pump chamber 192, i.e. the volume within the piston bore108 between the armature piston 146 and the valve seat 168. The coilwill continue to be energized for a brief time (e.g. a few milliseconds)in order to hold the armature piston 146 in the location illustrated inFIG. 3. The reduction in pressure within the pump chamber 192 will openthe main check valve 107 by overcoming the biasing force of the spring170 and move valve element 162 to the position illustrated in FIG. 4. Asa result, the valve head 166 will move away from the valve seat 168 andfluid will flow into the pump chamber 192. The main check valve 107 willclose, due to the force exerted by spring 170 on valve element 162, oncethe pressure within pump chamber 192 is equal to pressure at the inlettube 184. However, because the coil 138 continues to be energized, thearmature 132 will remain in the position illustrated in FIGS. 3 and 4 asfluid flows into the pump chamber 192 and the main check valve 107closes.

Immediately after the main check valve 107 closes, the coil 138 will bedisconnected from the energy source and the magnetic field establishedby the electromagnet 130 will decay until it can no longer overcome theforce exerted on the armature 132 by the main spring 150. The armature132 will then move back to the position illustrated in FIGS. 2 and 5.The associated increase in pressure within the pump chamber 192 issufficient to open the bypass valve 106 by overcoming the biasing forceof the spring 180 and moving the valve element 174 to the positionillustrated in FIG. 5. The increase in pressure within the pump chamber192, coupled with movement of the valve element away from the wall 178,results in the fluid flowing through the orifice 120 to the fluidchamber 122. The flow of fluid will cause the pressure in the orifice120 and the fluid chamber 122 to equalize. At this point, the bypassvalve 106 will close, due to the force exerted by spring 180 on thevalve element 174, thereby returning the exemplary fluid transfer device110 to the rest state illustrated in FIG. 2.

Additional general information concerning the exemplary fluid transferdevice 100, as well as other fluid transfer devices, may be found inU.S. Pat. Nos. 6,227,818 and 6,264,439 and U.S. Patent Pub. No.2007/0269322.

As alluded to above, the present inventors have determined that adhesionof a valve element to a valve seat, including an increase in adhesionover time in normally closed valves, can reduce the effectiveness of thefluid transfer device by increasing the threshold force required to openthe main check valve and, in turn, increasing the load on the batteryand reducing the amount of fluid that flows through the valve duringeach pump cycle. Such adhesion may also reduce the life of the valveseat. The present valve seats are configured to provide the samebiocompatibility and sealing capabilities as conventional valves seats,i.e. maintain a seal over a million or more open/close cycles and take aminimal compression set, in a manner that results in less adhesion ofthe valve seat to the valve element. To that end, the present valveelements include a main portion and a seal portion (or “non-stickportion”) that is configured to be less tacky than the main portion. Asused herein, a “less tacky” seal portion results in a lower adhesionbetween the valve seat and valve element (sometimes referred to as“pull-off adhesion”), after the same contact time and pressure, than anoverall identically shaped valve seat that includes seal portion that isnot configured to be less tacky. For example, the main portion, which ismajority of the present valve seats, may be formed from a material thatprovides the requisite sealing capabilities and the seal portion, whichwill contact the valve element when the valve is closed, may be formedfrom a material that is less tacky than the material that forms the mainportion. The seal portion may, alternatively, be a surface of the mainportion that has been treated in such a manner that it is less tackythan it was prior to the treatment.

Valve seats in accordance with the present inventions may have anyoverall shape and cross-sectional shape that is required for theassociated valve. The valve seats illustrated in FIGS. 6-17, forexample, have annular overall shapes and are rectangular incross-section. Other exemplary shapes are illustrated in FIGS. 18 and19.

The overall dimensions of the present main check valves and the elementsthereof will, of course, depend upon the particulars of the valve andthe associated fluid transfer device. In the exemplary context ofimplantable drug delivery devices, and although the volume/strokemagnitude may be increased in certain situations, the fluid transferdevices will typically deliver about 1 microliter/stroke, but may bemore or less (e.g. about 0.25 microliter/stroke or less) depending onthe particular fluid transfer device employed. One implementation ofsuch a fluid transfer device, the housing 102 will be about 10 mm longand about 7.5 mm in diameter, and the armature piston 146 will be about1.25 mm in diameter. The main check valve 107 associated with such afluid transfer device may have the following dimensions. The diametersof the housing fluid flow portion 163 and the mounting portion 165 areabout 2.5 mm and about 7.5 mm, respectively. The length of the valve107, i.e. the combined lengths of the fluid flow portion 163 and themounting portion 165 plus the thickness of the valve seat 168, is about2.5 mm. The outer diameter of the valve seat 168 will be about 2.5 mm,the inner diameter will be about 1 mm and the thickness will be about0.25 mm. The pull-off adhesion of the seal portion in some embodimentswill be less than about 0.5 psi in those instances where the valve seatopening is about 0.040 inch.

Referring first to FIGS. 6 and 7, the exemplary valve seat 168 has amain portion 194 and a seal portion 196. The seal portion 196 is theportion that is engaged by a portion of the valve element (e.g. valveelement head 166) when the main check valve is closed. Suitablematerials for the main portion 194 include, but are not limited to,silicone rubber, latex rubber, fluoropolymers, urethane, butyl rubber,and isoprene. Such materials allow the valve seat 168 to maintain a sealover a million or more open/close cycles and take a minimal compressionset. The seal portion 196 is a layer of silicon suboxide (SiO_(x)C_(y),where x<2 and y<1) such as, for example, SiO_(1.7)C_(0.4). The sealportion 196 is relatively thin and plasma deposition (or other suitabletechniques) may be used to deposit the silicon suboxide onto the mainportion 194. The thickness of a relatively thin layer of siliconsuboxide is about 0.1 μm to about 10 μm, and the seal portion 196 in theillustrated embodiment is about 0.3 μm to about 0.8 μm thick. The sealportion 196 may also cover the entire top surface of the main portion194 (as shown), only that part of the main portion top surface thatwould otherwise be engaged by the valve element head 166, or somethingin between.

The seal portion 196 may, in other implementations, be a layer of SiO₂that is about 0.1 μm to about 10 μm thick and formed by an oxygenatedplasma treatment of the main portion 194.

Another exemplary valve seat that may be included in a main check valve(e.g. main check valve 107) is generally represented by referencenumeral 168 a in FIGS. 8 and 9. The exemplary valve seat 168 a has amain portion 194 a and a seal portion 196 a. The seal portion 196 a isthe portion that is engaged by a portion of the valve element (e.g.valve element head 166) when the main check valve is closed. Suitablematerials for the main portion 194 include, but are not limited to,elastomers such as silicone rubber, latex rubber, fluoropolymers,urethane, butyl rubber, and isoprene. Such materials allow the valveseat 168 a to maintain a seal over a million or more open/close cyclesand take a minimal compression set. The seal portion 196 a is a layer ofa relatively hard durometer of the same class of material that is usedto form the main portion 194 a. As used in this context, a relativelyhard material is a material that is at least 50% harder than thematerial to which it is being compared. For example, if the main portion194 a is formed from a silicone rubber that has a hardness of about 40Shore A, then the seal portion 196 a may be formed from silicone rubberthat has a hardness of about 60-80 Shore A. Alternatively, instead of arelatively hard durometer of the same class of material, a relativelyhard durometer of one of the other main portion elastomers listed abovemay be used. The seal portion 196 a may be relatively thin and formed byplasma deposition, vapor deposition, chemical modification, comolding,dip coating, or spin coating. The thickness of a relatively thin layerof a relatively hard elastomer is about 0.001 mm to about 0.05 mm (e.g.about 0.001 mm if plasma deposited, about 0.025 mm if spin coated, andabout 0.05 mm if comolded or dip coated), and the seal portion 196 a inthe illustrated embodiment is about 0.05 mm thick. The seal portion 196a may cover the entire top surface of the main portion 194 a (as shown),only that part of the main portion top surface that would otherwise beengaged by the valve element head 166, or something in between.

Turning to FIGS. 10 and 11, another exemplary valve seat that may beincluded in a main check valve (e.g. main check valve 107) is generallyrepresented by reference numeral 168 b. The exemplary valve seat 168 bhas a main portion 194 b and a seal portion 196 b. The seal portion 196b is the portion that is engaged by a portion of the valve element (e.g.valve element head 166) when the main check valve is closed. Suitablematerials for the main portion 194 b include, but are not limited to,elastomers such as silicone rubber, latex rubber, fluoropolymers,urethane, butyl rubber, and isoprene. Such materials allow the valveseat 168 b to maintain a seal over a million or more open/close cyclesand take a minimal compression set. The seal portion 196 b is a layer ofmaterial with a hardness that is the same as, or is at least relativelyclose to (i.e. within 30%), the material that forms the main portion 194b, but that is less tacky than the material that forms the main portion.For example, if the main portion 194 b is formed from a silicone rubberthat is about 40 Shore A hardness, then the seal portion 196 b may beformed from, for example, a fluoroelastomer or a low friction (or“non-stick”) protective coating that is designed for use with silicone(e.g. a silicone coating polymer filled with particles such as that soldunder the trade name TopCoat) that has a hardness of about 40 Shore A.Other exemplary materials include aluminum oxide, silicone- orsilane-based coatings from NuSil Technologies LLC, titanium oxide,carbon (including carbon in the form of diamond or graphite), parylene,fluorosilicone, perfluorosilicone, ethylene propylene diene monomer(EPDM) rubber, halogenated rubber such as bromo/chlorobutyl rubber, andpolyisobutylene thermoplastic. The seal portion 196 b may be relativelythin and formed by spray coating, spin coating, or dip coating. Thethickness of a relatively thin layer of a less tacky layer (e.g. afluoroelastomer or a low friction coating) is about 0.01 mm to about0.05 mm, and is about 0.025 mm thick in the illustrated embodiment. Theseal portion 196 b may cover the entire top surface of the main portion194 b (as shown), only that part of the main portion top surface thatwould otherwise be engaged by the valve element head 166, or somethingin between.

A layer that is less tacky than a silicone main portion 194 b may alsobe formed by treating the silicone main portion with a lubricating agentsuch as MDX4-4120 from Dow Corning or fluoro oil. These lubricatingagents absorb into the silicone to form a less tacky layer that definesthe seal portion 196 b.

Another exemplary valve seat that may be included in a main check valve(e.g. main check valve 107) is generally represented by referencenumeral 168 c in FIGS. 12 and 13. The exemplary valve seat 168 c has amain portion 194 c and a seal portion 196 c. The seal portion 196 c isthe surface that is engaged by a portion of the valve element (e.g.valve element head 166) when the main check valve is closed. Suitablematerials for the main portion include, but are not limited to,elastomers such as silicone rubber, latex rubber, fluoropolymers,urethane, butyl rubber, and isoprene. Such materials allow the valveseat 168 c to maintain a seal over a million or more open/close cyclesand take a minimal compression set. The seal portion 196 c is ahalogenated surface of the main portion 194 c and the halogenatedsurface is less tacky than the material which forms the main portion.The seal portion 196 c (or “halogenated surface”) is formed by treatinga surface of the main portion with a halogen such as, for example,chlorine, fluorine or bromine. The thickness of the halogen may be, forexample, about 1 molecular layer (e.g. about 0.1 to about 1 nanometers).The seal portion 196 c may cover the entire top surface of the mainportion 194 c (as shown), only that part of the main portion top surfacethat would otherwise be engaged by the valve element head 166, orsomething in between.

Turning to FIGS. 14 and 15, another exemplary valve seat that may beincluded in a main check valve (e.g. main check valve 107) is generallyrepresented by reference numeral 168 d. The exemplary valve seat 168 dhas a main portion 194 d and a seal portion 196 d. The seal portion 196d is the surface that is engaged by a portion of the valve element (e.g.valve element head 166) when the main check valve is closed. Suitablematerials for the main portion include, but are not limited to,elastomers such as silicone rubber, latex rubber, fluoropolymers,urethane, butyl rubber, and isoprene. Such materials allow the valveseat 168 d to maintain a seal over a million or more open/close cyclesand take a minimal compression set. The seal portion 196 d is anion-implanted surface, or an ion-beam assisted ion-implanted/coatedsurface, of the main portion 194 d and is less tacky than the mainportion. The seal portion 196 d (or “ion-implanted surface” or“ion-implanted/coated surface”) is formed by ion-implanting a ceramicmaterial (e.g. aluminum oxide), a metal material (e.g. titanium) or ametal-oxide (e.g. titanium dioxide) into a surface of the main portion.The implanted ions may be distributed randomly and interstitially (e.g.on the surface, below the surface, and partially implanted into thesurface). It should be noted that, even if the ions are subsequentlyremoved, the surface will be less tacky than it was prior to thetreatment because the ion-implantation process changes the internalchemical structure in the silicone rubber or other elastomeric materialthat forms the main portion 194 d. Alternatively, ion-implantation maybe combined with a deposition step that first implants and then depositsa thin layer of the implanted material on top of the surface of the mainportion. For example, a layer that is about 100 nanometers thick with animplantation depth of about 1 micron may be formed on the main portion194 d.

Another exemplary valve seat that may be included in a main check valve(e.g. main check valve 107) is generally represented by referencenumeral 168 e in FIGS. 16 and 17. The exemplary valve seat 168 e has amain portion 194 e and a seal portion 196 e. The seal portion 196 e isthe portion that is engaged by a portion of the valve element (e.g.valve element head 166) when the main check valve is closed. Suitablematerials for the main portion include, but are not limited to,elastomers such as silicone rubber, latex rubber, fluoropolymers,urethane, butyl rubber, and isoprene. Such materials allow the valveseat 168 e to maintain a seal over a million or more open/close cyclesand take a minimal compression set. The seal portion 196 e is a coatingof a filler (e.g. fumed silica, ground mica, talc, Teflon®, TiO₂, bariumsulfate, etc.) that reduces the contact area and surface interactionbetween the valve element and the tackier material (e.g. siliconerubber) which forms the main portion 194 e. The seal portion 196 e maybe relatively thin and formed by comolding, plasma etching to expose thefiller material on the surface, or applying a thin coating of the filledmaterials on an unfilled main portion. The thickness of a relativelythin layer of a filler is about 0.025 mm to about 0.075 mm thick, and inthe illustrated embodiment, is about 0.05 mm thick. The seal portion 196e may cover the entire top surface of the main portion 194 e (as shown)or only that portion of the main portion top surface that wouldotherwise be engaged by the valve element head 166.

As noted above, valve seats in accordance with the present inventionsmay have shapes other than the annular shape illustrated in FIGS. 6-17.For example, the exemplary valve seat 168 f illustrated in FIG. 18 has amain portion 194 f, with a raised area 195 f, and a seal portion 196 f.The raised area 195 f, which is semi-circular in cross-section andcircular in plan in the illustrated embodiment, reduces the contact areabetween valve seat 168 f and the valve element head 166. This, in turn,increases the sealing pressure, as compared to a sealing arrangementwith a flat valve head and a flat valve seat. Additionally, although theraised area 195 f will flatten slightly when the main check valve 107 fis closed, the curved raised area will reduce the amount of flat-on-flatsurface area as well as the adhesion force associated therewith. Themain portion 194 f and seal portion 196 f may be formed by the samematerials, using the same manufacturing processes, as the main portionsand seal portions described above in the context of FIGS. 6-17.

Another exemplary valve seat that does not have a purely annular shapeis generally represented by reference numeral 168 g in FIG. 19. Thevalve seat 168 g, which includes a main portion 194 g and a seal portion196 g, is configured to be incorporated into a low ullage valve 107 gwith a valve element 162 g. The valve element 162 g includes an endportion, such as the illustrated head 166 g , that is shaped like atruncated cone, and the valve seat 168 g includes a correspondinglyshaped indentation 171 g that extends to the valve seat opening 169 g.Such shapes allow the valve element head 166 g to nest in the valve seat168 g. The seal portion 196 g is associated with the indentation and,depending on the manner in which the seal portion is produced, may alsobe associated with the opening 169 g. The main portion 194 g and sealportion 196 g may be formed from the same materials, using the samemanufacturing processes, as the main portions and seal portionsdescribed above in the context of FIGS. 6-17.

As illustrated above, the seal portions 196-196 g each perform thefunction of making a surface of the associated valve seat less tackythan the material elastomeric material which forms the main portion194-194 g.

Referring to FIG. 20, and as discussed in detail above, fluid transferdevices in accordance with some of the present inventions may include apump and a main check valve. The pump may be, by way of example but notlimitation, an electromagnet pump, a solenoid pump, a piezoelectricpump, or any other mechanical or electromechanical pulsatile pump, themain check valve may be any of the main check valves described aboveand, accordingly, the present fluid transfer devices include any and allcombinations of such pumps and main check valves. The present fluidtransfer device may also include a bypass valve. One example of such abypass valve is generally represented by reference numeral 106 inFIG. 1. Fluid entering such fluid transfer devices will typically passthe main check valve prior to being acted on by the pump, and will passthe bypass valve on its way to the outlet after being acted one by thepump.

One example of an implantable infusion device that may include any ofthe valve seats, valves and/or fluid transfer devices described above isgenerally represented by reference numeral 200 in FIGS. 21-24. As usedherein, an “implantable infusion device” is a device that includes areservoir and an outlet, and is sized, shaped and otherwise constructed(e.g. sealed) such that both the reservoir and outlet can besimultaneously carried within the patient's body. The exemplary infusiondevice 200 includes a housing 202 (e.g. a titanium housing) with abottom portion 204, an internal wall 206, and a cover 208. An infusiblesubstance (e.g. medication) may be stored in a reservoir 210 that islocated within the housing bottom portion 204. The reservoir 210 may bereplenished by way of a fill port 212 that extends from the reservoir,through the internal wall 206, to the cover 208. A hypodermic needle(not shown), which is configured to be pushed through the fill port 212,may be used to replenish the reservoir 210.

A wide variety of reservoirs may be employed. In the illustratedembodiment, the reservoir 210 is in the form of a titanium bellows withan end wall 211 that is positioned within a sealed volume defined by thehousing bottom portion 204 and internal wall 206. The remainder of thesealed volume is occupied by propellant P, which may be used to exertnegative pressure on the reservoir 210. Other reservoirs that may beemployed in the present infusion devices include reservoirs in whichpropellant exerts a positive pressure. Still other exemplary reservoirsinclude negative pressure reservoirs that employ a movable wall that isexposed to ambient pressure and is configured to exert a force thatproduces an interior pressure which is always negative with respect tothe ambient pressure.

The exemplary ambulatory infusion device 200 illustrated in FIGS. 21-24also includes the fluid transfer device 100. The inlet of the fluidtransfer device 100 is coupled to the interior of the reservoir 210 by apassageway 214, while the outlet of the fluid transfer device is coupledto an outlet port 216 by a passageway 218. Operation of the fluidtransfer device 100 causes infusible substance to move from thereservoir 210 to the outlet port 216. A catheter 220 may be connected tothe outlet port 216 so that the infusible substance passing through theoutlet port will be delivered to a target body region in spaced relationto the infusion device 200 by way of the outlet(s) 222 at or near theend of the catheter.

Energy for the fluid transfer device 100, as well for other aspects ofthe exemplary infusion device 200, is provided by the battery 224illustrated in FIG. 22. In the specific case of the fluid transferdevice 100, the battery 224 is used to charge one or more capacitors226, and is not directly connected to the fluid transfer device itself.The capacitor(s) 226 are connected to an electromagnet coil in the fluidtransfer device 100, and disconnected from the battery 224, when theelectromagnet coil is being energized, and are disconnected from theelectromagnet coil and connected to the battery when the capacitor(s)are being recharged and/or when the fluid transfer device is at rest.The capacitor(s) 226 are carried on a board 228. A communication device230, which is connected to an antenna 232, is carried on the same sideof the board 228 as the capacitor(s) 226. The exemplary communicationdevice 230 is an RF communication device. Other suitable communicationdevices include, but are not limited to, oscillating magnetic fieldcommunication devices, static magnetic field communication devices,optical communication devices, ultrasound communication devices anddirect electrical communication devices.

A controller 234 (FIG. 24), such as a microprocessor, microcontroller orother control circuitry, is carried on the other side of the board 228.The controller controls the operations of the infusion device 200 inaccordance with instructions stored in memory 236 and/or provided by anexternal device (e.g. a remote control programmer) by way of thecommunication device 230. For example, the controller 234 may be used tocontrol the fluid transfer device 100 to supply fluid to the patient inaccordance with, for example, a stored basal delivery schedule or abolus delivery request. The controller 234 may also be used to monitorsensed pressure and perform the analytical functions described below.

Referring to FIGS. 21, 22 and 24, the exemplary infusion device 200 isalso provided with a side port 238 that is connected to the passageway218 between the outlet of the fluid transfer device 100 and the outletport 216. The side port 238 facilitates access to an implanted catheter220, typically by way of a hypodermic needle. For example, the side port238 allows clinicians to push fluid into the catheter 220 and/or drawfluid from the catheter for purposes such as checking catheter patency,sampling CSF, injecting contrast dye into the patient and/or catheter,removing medication from the catheter prior to dye injection, injectingadditional medication into the region at the catheter outlet 222, and/orremoving pharmaceuticals or other fluids that are causing an allergic orotherwise undesirable biologic reaction.

The outlet port 216, a portion of the passageway 218, the antenna 232and the side port 238 are carried by a header assembly 240. The headerassembly 240 is a molded, plastic structure that is secured to thehousing 202. The housing 202 includes a small aperture through whichportions of the passageway 218 are connected to one another, and a smallaperture through which the antenna 232 is connected to the board 228.

The exemplary infusion device 200 illustrated in FIGS. 21-24 alsoincludes a pressure sensor 242 that is connected to the passageway 218between the outlet of the fluid transfer device 100 and the outlet port216. As such, the pressure sensor 242 senses the pressure at the outletport 216 which, in the illustrated embodiment, is also the pressurewithin the catheter 220. The pressure sensor 242 is connected to thecontroller 234 and may be used to analyze a variety of aspects of theoperation of the exemplary implantable infusion device 200. For example,pressure measurements may be used by the controller 234 to determinewhether or not there is a blockage in the catheter 220 and whether ornot the fluid transfer device 100 is functioning properly. Thecontroller 234 may perform a variety of different functions in responseto a determination that the fluid transfer device 100 is not functioningproperly or a determination that the catheter 220 is blocked. Forexample, the controller 234 may actuate an audible alarm 244 that islocated within the housing 202 in order to signal that the fluidtransfer device 100 is not functioning properly or the catheter 220 isblocked.

The present inventions are also applicable to other types of valves.Referring first to FIG. 25, the exemplary bypass valve 106 a isessentially identical to the bypass valve 106 and similar elements arerepresented by similar reference numerals. Here, however, theelastomeric valve element 174 a includes a main portion 246 and a sealportion 248. The seal portion 248 may cover the entire surface of themain portion 246 that faces/engages the wall (or “seat”) 178, as shown,or may merely cover the sealing ring 176. The main portion 246 and sealportion 248 may be formed from the same materials, using the samemanufacturing methods, as the valve seat main portions 194-194 g andseal portions 196-196 g described above. The end region of the mainportion 246 that faces the wall (or “seat”) 178, and the seal portion248, define one example of a valve element end portion. The bypass valve106 a may be included in fluid transfer devices such as the exemplaryfluid transfer device 100 and/or may be included in implantable infusiondevices such as the implantable infusion device 200.

Another exemplary valve is the outlet valve 250 illustrated in FIG. 26,which is shown in its open position in a fluid transfer device 252 thatincludes a housing 254 and a pump with a piston 256 in a piston bore258. The piston 256 is driven by an electromagnet and spring arrangement(not shown). The exemplary outlet valve 250, which is in fluidiccommunication with the pump, includes a housing which is incorporatedinto the housing 254, an elastomeric valve element 262, a valve elementretainer 264, and a spring 266 that biases the valve element against thewall (or “seat”) 268 which extends around the piston bore 258. Thesurface of the valve element 262 that engages the wall 268 may beuneven, as shown, flat, or any other suitable shape. The valve element262 also includes a main portion 270 and a seal portion 272. The valveelement main portion 270 and seal portion 272 may be formed from thesame materials, using the same manufacturing methods, as the valve seatmain portions 194-194 g and seal portions 196-196 g described above. Theend region of the main portion 270 that faces the wall (or “seat”) 268,and the seal portion 272, define one example of a valve element endportion. The exemplary spring 266 may be of any suitable configurationthat will permit the passage of fluid and, in the illustratedembodiment, includes a plurality of spaced radially extending arms thatfit into a circumferentially extending slot 274 within the housing 254.The outlet valve 250 may be included in a wide variety of fluid transferdevices and/or implantable infusion devices such as, for example, thoseillustrated in U.S. Patent No. 7,131,967.

Yet another exemplary valve is the regulator valve 276 in the pressureregulator 278 illustrated in FIG. 27. The regulator valve 276 includesan elastomeric valve seat 280, with a main portion 282 and a sealportion 284, and a valve element 286 with an end portion, such as theillustrated head, that engages valve seat. The main portion 282 and sealportion 284 may be formed from the same materials, using the samemanufacturing methods, as the valve seat main portions 194-194 g andseal portions 196-196 g described above. Although not limited to anyparticular configuration, the exemplary pressure regulator 276 alsoincludes a housing 288 with an inlet 290, outlets 292, and a sealedbellows 294 that provides a reference pressure and carries the valveelement 286. The pressure regulator 278 may be employed in animplantable infusion device (e.g. the implantable infusion device 200)upstream or downstream of the reservoir, either in direct or indirectfluidic communication with the pump, to prevent unintended dischargefrom the catheter as a result of over pressurization. Other exemplarypressure regulator configurations that may include a valve seat (orvalve element) with the above-described main portion and seal portionconfigurations are disclosed in U.S. Pat. Pub. No. 2005/0273083.

Still another exemplary valve is the fill port valve 296 illustrated inFIG. 28, which opens and closes based on the volume of fluid within theassociated reservoir to prevent an overfill. Although not limited to usein combination with any particular infusion device, the exemplary fillport valve 296 is shown in combination with the exemplary infusiondevice 200 and, to that end, the infusion device fill port 212 mayinclude a chamfered inlet 213 and a septum 215. The exemplary fill portvalve 296, which is in fluidic communication with the electromagnet pump104 by virtue of its association with the reservoir 210, includes anouter housing portion 298 that is secured to the internal wall 206, aninner housing portion 300 with a valve seat 302 and valve seat lumens304, a fixed cylinder 306 which functions as a needle stop and has aplurality of outlets 308 at various locations, a movable cylinder 310which carries a valve element 312 a main portion 314 and a seal portion316. The seal portion 316 covers the entire surface of the main portion314 that faces/engages the valve seat 302. The main portion 314 and sealportion 316 may be formed from the same materials, using the samemanufacturing methods, as the valve seat main portions 194-194 g andseal portions 196-196 g described above. The end region of the mainportion 314 that faces the valve seat 302, and the seal portion 316,define one example of a valve element end portion. A spring or otherbiasing device 318, which is positioned at one end of the movablecylinder 310, biases the movable cylinder (and valve element 312) towardthe valve seat 302. The other end of the movable cylinder 310 abuts theinner surface of the reservoir end wall 211. When the reservoir 210 isrelatively empty, the force associated with the reservoir will overcomethe force associated with the spring 318 and the movable cylinder 310and valve element 312 will be in the position illustrated in FIG. 28.

The reservoir 210 may be filled by inserting a needle (not shown) intothe fill port 212 and injecting fluid into the fixed cylinder 306. Thefluid will flow into the reservoir 210 by way of the fixed cylinderoutlets 308, the open end of the movable cylinder 310, and the valveseat lumens 304. The reservoir end wall 211 will move away from the wall206 as the reservoir 210 fills with fluid. As this occurs, the biasingforce of the spring 318 will drive the movable cylinder 310 away fromthe fill port 212. The reservoir 210 and fill port valve 296 arerespectively configured such that, when the reservoir is full, the valveelement 312 will engage the valve seat 302 and prevent additional flowthrough the valve seat lumens 304, thereby preventing an overfillcondition.

Another exemplary fill port valve is generally represented by referencenumeral 320 in FIG. 29. One example of an infusion device that mayinclude the fill port valve 320 is the exemplary infusion device 200,which may have a fill port 212 with a chamfered inlet 213 and a septum215. The fill port valve 320, which is in fluidic communication with theelectromagnet pump 104 by virtue of its association with the reservoir210, includes a housing 322 that is secured to the internal wall 206, avalve seat 324, and a valve element 326. The valve element 326, whichhas a main portion 328 and a seal portion 330, is carried by a valveelement retainer 332 that is secured to the reservoir end wall 211 by apost 334. The main portion 328 and seal portion 330 may be formed fromthe same materials, using the same manufacturing methods, as the valveseat main portions 194-194 g and seal portions 196-196 g describedabove. The end region of the main portion 328 that faces the seat 324,and the seal portion 330, define one example of a valve element endportion. When the reservoir 210 is relatively empty, the valve element326 will be in the position illustrated in FIG. 29.

The reservoir 210 may be filled by inserting a needle (not shown) intothe fill port 212 and injecting fluid into the housing 322. The fluidwill flow into the reservoir 210 by way of an opening 336 in the valveseat 324 and the reservoir end wall 211 will move away from the wall 206as the reservoir fills with fluid. The valve element 326 will move awayfrom the fill port 212 by virtue of its connections to the reservoir endwall 211. The reservoir 210 and fill port valve 320 are respectivelyconfigured such that, when the reservoir is full, the valve element 326will engage the valve seat 324 and prevent additional flow through thevalve seat opening 336, thereby preventing an overfill condition.

Still another exemplary fill port valve is generally represented byreference numeral 338 in FIG. 30. One example of an infusion device thatmay include the fill port valve 338 is the exemplary infusion device200, which may have a fill port 212 with a chamfered inlet 213 and aseptum 215, The exemplary fill port valve 338 illustrated in FIG. 30,which is in fluidic communication with the electromagnet pump 104 byvirtue of its association with the reservoir 210, is substantiallysimilar to the valve illustrated in FIG. 29 and similar elements arerepresented by similar reference numerals. Here, however, the valve 338includes a valve element 342 that is secured to the reservoir end wall211. A valve seat 340, which has a main portion 344 and a seal portion346, is secured to the housing 322. The main portion 344 and sealportion 346 may be formed from the same materials, using the samemanufacturing methods, as the valve seat main portions 194-194 g andseal portions 196-196 g described above. When the reservoir 210 isrelatively empty, the valve element end portion, e.q., the illustratedhead 348, will be in spaced relation to valve seat 340 so that fluid mayflow though the valve seat opening 350.

The reservoir 210 may be filled by inserting a needle (not shown) intothe fill port 212 and injecting fluid into the housing 322. The fluidwill flow into the reservoir 210 by way of an opening 350 in the valveseat 340 and the reservoir end wall 211 will move away from the wall 206as the reservoir fills with fluid. The valve element 342 will also moveby virtue of its connection to the reservoir end wall 211. The reservoir210 and fill port valve 338 are respectively configured such that, whenthe reservoir is full, the valve element head 348 will engage the valveseat 340 and prevent additional flow through the valve seat opening 350,as is shown in FIG. 30, thereby preventing an overfill condition.

Additional details concerning valves such as those illustrated in FIGS.28-30, which open and close as a function of the volume of fluid withinthe reservoir, may be found in U.S. Pat. No. 5,158,547.

Another exemplary valve is the in-line pressure check valve 352illustrated in FIG. 31, which uses a reference pressure to regulateflow. Although not limited to use in combination with any particularinfusion device, the exemplary in-line pressure check valve 352 may beused in combination with the exemplary infusion device 200 andpositioned between the reservoir 210 and fill port 212. The exemplaryvalve 352, which is in fluidic communication with the electromagnet pump104 by virtue of its association with the reservoir 210, includes a base354 with an annular chamber 356 and a central lumen 358, a controlelement 360 with lumens 362 and a valve element 364 with an end portionthat faces a valve seat 368, and a flexible annular membrane 366 thatseals the annular chamber 356 such that a reference pressure may bemaintained within the chamber. The portion of the annular member 366that is aligned with the valve element 364 is the valve seat 368. Thevalve seat 368 includes a main portion 370 and a seal portion 372 thatmay be formed from the same materials, using the same manufacturingmethods, as the valve seat main portions 194-194 g and seal portions196-196 g described above.

The exemplary in-line pressure check valve 352 is shown in its openstate in FIG. 31. Fluid flowing from, for example, the fill port willpass though the control element lumens 362 and the base central lumen358. Should the pressure of the fluid increase to a pressure that isgreater than the reference pressure within the annular chamber 356, theflexible annular membrane 366 will deform into the annular chamber. Thevalve element 364 will then engage the valve seat 368, therebypreventing flow through the central lumen 358, when the fluid pressurereaches the rated pressure of the valve 352. Additional detailsconcerning valves such as that illustrated in FIG. 31 may be found inU.S. Pat. No. 5,725,017.

The exemplary in-line pressure check valve 352 may also be modified in avariety of ways. For example, the pressure check valve 352 a illustratedin FIG. 32 is substantially similar to the check valve 352 and similarelements are represented by similar reference numerals. Here, however,there is a separate valve seat 368 a that is not part of the annularmembrane 366. The valve seat 368 a includes a main portion 370 a and aseal portion 372 a that may be formed from the same materials, using thesame manufacturing methods, as the valve seat main portions 194-194 gand seal portions 196-196 g described above. Turning to FIG. 33, thein-line pressure check valve 352 b illustrated in FIG. 32 issubstantially similar to the check valve 352 and similar elements arerepresented by similar reference numerals. Here, however, the base 354 bincludes a valve seat 368 b and the control element 360 b carries avalve element 364 b with main portion 370 b and a seal portion 372 b.The main portion 370 b and seal portion 372 b may be formed from thesame materials, using the same manufacturing methods, as the valve seatmain portions 194-194 g and seal portions 196-196 g described above. Theend region of the main portion 370 b that faces the valve seat 368 b,and the seal portion 372 b, define one example of a valve element endportion.

Another valve which uses a reference pressure to regulate flow is theexemplary pressure sensitive valve 374 illustrated in FIG. 34. Oneexample of an infusion device that may include the valve 374 is theexemplary infusion device 200. The exemplary valve 374, which is influidic communication with the electromagnet pump 104 by virtue of itsassociation with the reservoir 210, includes a housing 376 with an inletport 378 that is in fluid communication with the fill port 212, and arecess 380 that is covered by a plate 382 with apertures 384. A valveseat 386 with a lumen 388 is secured to the housing 376 and a valveelement 390, with an end portion (e.g., the illustrated head 392) and apost 394, is positioned for movement relative to the valve seat. Thevalve seat 386 includes a main portion 396 and a seal portion 398 thatmay be formed from the same materials, using the same manufacturingmethods, as the valve seat main portions 194-194 g and seal portions196-196 g described above. The valve element 390 is biased toward theclosed position, i.e. with the head 392 in contact with the valve seat386, by a spring 400 or other suitable biasing element, and is biasedtoward the illustrated open position by collapsible sealed structure (or“aneroid”) 402 that is secured to the post 394 and has an internalvolume which is occupied by a fluid at a reference pressure.

The reference pressure within the sealed structure 402 will maintain thevalve element 390 in the open position so that fluid may flow from thefill port to the reservoir 210 by way of the inlet port 378, lumen 388and apertures 384. Should fluid flow continue after the reservoir 210 isfull, the pressure on the exterior of the sealed structure 402 willincrease to the point at which it will collapse. The collapse of thesealed structure 402 allows the spring 400 to drive the valve element390 to its closed position where the head 392 is against the valve seat386 and fluid is prevented from flowing through the lumen 388.Additional details concerning valves such that illustrated in FIG. 34may be found in U.S. Pat. No. 6,152,898.

The exemplary pressure sensitive valve 374 may also be modified in avariety of ways. As illustrated for example in FIG. 35, a valve element404, which has a main portion 406 and a seal portion 408, may be carriedby a valve element retainer 410 that is secured to the sealed structure402 by a post 412. The main portion 406 and seal portion 408 may beformed from the same materials, using the same manufacturing methods, asthe valve seat main portions 194-194 g and seal portions 196-196 gdescribed above. The valve element 404 will move in and out of contactwith the valve seat 386 a in response to pressure changes in the mannerdescribed above. The end region of the main portion 406 that faces thevalve seat 386 a, and the seal portion 408, define one example of avalve element end portion.

Turning to FIG. 36, the exemplary implantable infusion device 200 a issubstantially similar to the implantable infusion device 200 describedabove with reference to FIGS. 21-24 and similar elements are representedby similar reference numerals. Here, however, the implantable infusiondevice 200 a includes catheter apparatus 414 with a header assembly 240a, a strain relief element 416 and a catheter 220. The header assembly240 a, which may be removably secured to the housing 202 a in, forexample, the manner described in U.S. Pat. No. 5,466,218, includes acheck valve 418 between the catheter 220 and the side port 238. Thecheck valve 418 is in fluid communication with the pump 104 when theheader assembly 240 a is secured to the housing 202 a.

As illustrated in FIG. 37, the exemplary check valve 418 includes ahousing 420 with an inlet 422 and an outlet 424, a valve seat 426, avalve element 428 with an end portion that faces the valve seat, and aspring 430 or other biasing device that biases the valve element to theclosed position illustrated in FIG. 37. An o-ring 432 may be positionedbetween the valve element 428 and the spring 430. The housing may be anintegral portion of the header assembly 240 a (as shown) or may be aseparate structural element. The exemplary valve element 428 isspherical and the valve seat 426 is configured to receive the sphericalvalve element. The valve seat 426 also includes a main portion 434 and aseal portion 436 that may be formed from the same materials, using thesame manufacturing methods, as the valve seat main portions 194-194 gand seal portions 196-196 g described above. In other configurations,the valve element may be provided with a main portion and a seal portionformed from the same materials, using the same manufacturing methods, asthe valve seat main portions 194-194 g and seal portions 196-196 gdescribed above.

Another exemplary catheter assembly, which is generally represented byreference numeral 414 a in FIG. 38, includes a catheter 220, a strainrelief element 416 a and a check valve 418 a. The check valve 418 a isessentially identical to the check valve 418 but for its location withinthe strain relief element 416 a. The catheter assembly 414 a may, insome instances, also include a removable header assembly such as thatillustrated in FIG. 36.

Turning to FIG. 39, still another exemplary catheter assembly 414 bincludes a catheter 220 and a check valve 418 b. The check valve 418 bis essentially identical to the check valve 418 but for its size and itslocation within the catheter 220. The catheter assembly 414 b may, insome instances, also include a strain relief element and/or a removableheader assembly such as those illustrated in FIGS. 36 and 38.

The present inventions are also applicable to other types of ambulatoryinfusions devices and the valves employed therein. To that end, anotherexample of an ambulatory infusion device in accordance with a presentinvention is the implantable infusion device generally represented byreference numeral 500 in FIGS. 40 and 41. The implantable infusiondevice 500 is similar to the implantable infusion device 200 in manyrespects and similar elements are represented by similar referencenumerals. To that end, the exemplary infusion device 500 includes ahousing 502 (e.g. a titanium housing) with a bottom portion 504, aninternal wall 506, and a cover 508. An infusible substance (e.g.medication) may be stored in a reservoir 510 that is located within thehousing bottom portion 504. The reservoir 510 may be replenished by wayof a refill port 512 that extends from the reservoir, through theinternal wall 506, to the cover 508. A hypodermic needle (not shown),which is configured to be pushed through the refill port 512, may beused to replenish the reservoir 510. The reservoir 510 in the exemplaryinfusion device 500 is a positive pressure reservoir and, in theillustrated embodiment, the reservoir is in the form of a titaniumbellows that is positioned within a sealed volume defined by the housingbottom portion 504 and internal wall 506. The remainder of the sealedvolume is occupied by a propellant P that exerts a positive pressure onthe bellows.

The exemplary infusion device 500 also includes a fluid transfer device100 a that is configured for use in combination with a positive pressurereservoir such as the exemplary positive pressure reservoir 510. In theillustrated embodiment, the fluid transfer device 100 a has anaccumulator 544 that includes a housing 546, a diaphragm 548 (e.g. aflexible sheet of titanium), an inlet 550, and an outlet 552. The fluidtransfer device 100 a also has an active inlet valve 554, which controlsthe flow of fluid into the housing inlet 550, and an active outlet valve556, which controls the flow of fluid out of the housing outlet 552. Theactive inlet valve 554 is also connected to the interior of the positivepressure reservoir 510, while the active outlet valve 556 is alsoconnected to the outlet port 516 which, in turn, may be connected to thecatheter 520. The exemplary active valves 554 and 556 are discussed ingreater detail below with reference to FIGS. 42 and 43.

During operation of the fluid transfer device 100 a, infusible substancewill move from the positive pressure reservoir 510 to an accumulatorcavity 558, which is defined by the housing 546 and the diaphragm 548,when the active inlet valve 554 is opened. A pressure chamber 562 islocated on the other side of the diaphragm 548. The active outlet valve556 will be closed while the inlet valve 554 is opened. The diaphragm548 will flex due to the positive pressure from the reservoir until itreaches a stop 560, as is shown in dashed lines in FIG. 41, therebyincreasing the volume of the accumulator cavity 558 by a predeterminedamount. The active inlet valve 554 will then be allowed to close. Whenthe active outlet valve 556 is opened, the pressure within the chamber562 will drive the diaphragm 548 back to the solid line position,thereby driving the predetermined volume of fluid to the outlet port516.

Although the present fluid transfer device 100 a is not so limited, theactive inlet and outlet valves 554 and 556 in the illustrated embodimentare identical electromagnet valves that may be selectively actuated in amanner similar to the electromagnet pumps described above. Turning toFIG. 42, the exemplary active inlet valve 554 (and outlet valve 556)includes a generally solid, cylindrical housing 602 with various openregions that accommodate portions of various structures and define afluid flow path. More specifically, the housing 602 includes an inlet604, an outlet 606 and an open region 608. The inlet 604 may be used asan outlet, and the outlet 606 may be used as an inlet, when thedirection of fluid flow through the valve 554 is reversed. A springretainer 610, with apertures 612 to permit fluid flow and a bore 614, ismounted within the housing 602.

An elastomeric valve element 616 is movable in to and out of engagementwith a rigid valve seat 618 that is associated with the outlet 606. Thevalve element 616 includes a main portion 617 and a seal portion 619.The valve element main portion 617 and seal portion 619 may be formedfrom the same materials, using the same manufacturing methods, as thevalve seat main portions 194-194 g and seal portions 196-196 g describedabove. The elastomeric valve element 616 is supported on a valve elementretainer 620 that includes a shaft 622, a spring retainer 624 and ananchor 625. A spring 626 (e.g. a coil spring), which is mounted betweenthe spring retainers 610 and 624, biases the valve element retainer 620to the closed position illustrated in FIG. 42 such that the valveelement 616 engages the valve seat 618.

With respect to actuation, the exemplary active valve 554 also includesan electromagnet 628 and an armature 630. The electromagnet 628, whichis carried within a case 632 that is secured to the housing 602, has acore 634 and a coil 636. The case 632 and core 634 are made from amagnetic material. The coil 636 consists of a wire or other conductorthat is wound around the core 634. The coil 636 may be insulated fromthe case 632 by electrically non-conductive spacers (not shown), whichcenter the coil within the case, or through the use of potting compoundor encapsulant material between the case and the coil. A barrier 638separates the open region 608, which will ultimately be filled withfluid, from the electromagnet 628. The armature 630 consists of a pole644 formed from a magnetic material (e.g. magnetic steel), which islocated within the open region 608 such that it will be magneticallyattracted to the electromagnet 628 when the electromagnet is actuated,and a hollow cylindrically-shaped bushing 646 that extends from the poleand into the bore 614 and is slidable relative to the bore. The valveelement retainer shaft 622 is fixedly secured (e.g. through a press fit)to the armature pole 644 by way of the bushing 646. The magneticattraction between the actuated electromagnet 628 and the armature pole644 is sufficient to overcome the biasing force of the spring 626 andmove the valve element 616 away from the valve seat 618 to open theactive valve 554.

The exemplary valve seat 618 illustrated in FIG. 42, which is rigid andhas an overall circular shape, includes a main portion 648 and a curvedsurface 650 that is semi-circular or otherwise curved in cross-section.The curved surface 650 reduces the contact area between the valve seat618 and the valve element 616, which in turn increases the sealingpressure, as compared to a sealing arrangement that has two flatsurfaces. The curved surface 650 also eliminates the adhesion forceassociated with flat on flat contact surfaces. The scuffing issuediscussed above is also obviated because the rigid valve seat 618 doesnot have sharp edges that come into contact with the elastomeric valveelement 616.

In other implementations, a substantially rigid valve element 616 a(FIG. 43) may be provided with a curved surface 650 a that issemi-circular or otherwise curved in cross-section and is carried by avalve element carrier 620 a. The curved surface 650 a engages anelastomeric valve seat 618 a when the valve is closed. This arrangementis analogous to, and provides the same benefits as, the curved sealarrangement illustrated in FIG. 42. The valve seat 616 a includes a mainportion 621 and a seal portion 623. The valve seat main portion 621 andseal portion 623 may be formed from the same materials, using the samemanufacturing methods, as the valve seat main portions 194-194 g andseal portions 196-196 g described above.

With respect to manufacturing and materials, the exemplary housing 602is a machined part and suitable materials for the housing include, butare not limited to, titanium, titanium alloys, stainless steel (e.g.316L stainless steel), cobalt-nickel alloys, and refractory metals suchas tantalum. The valve element retainer 620 may also be machined andsuitable materials for the machined valve element include, but are notlimited to, those described above in the context of the housing 602.Alternatively, the valve element retainer 620 may be molded. Suitablematerials for a molded valve element include, but are not limited to,polyolefins, liquid crystal polymers, PEEK, polyacetal plastics such asDelrin®, fluoropolymers, and most other molded materials that are rigidand inert to pharmaceuticals.

Additional information concerning the exemplary fluid transfer device100 a and/or active valves may be found in U.S. Pat. Nos. 4,838,887 and5,368,274, which are incorporated herein by reference. It should also benoted here that, although the active valves in the illustratedembodiments include electromagnet actuators, other types of actuatorsmay also be employed. For example, solenoid and piezoelectric actuatorsmay be employed.

Energy for the active valves 554 and 556, as well for other aspects ofthe exemplary infusion device 500, is provided by the implantableinfusion device battery (not shown). The battery charges one or morecapacitors in the manner described above, and is not directly connectedto the active valves themselves. The capacitor(s) are selectivelyconnected to one of the electromagnet coils 636 in the active valves 554and 556, and disconnected from the battery, when an electromagnet coilis being energized, and are disconnected from the electromagnet coilsand connected to the battery when the capacitor(s) are being rechargedand/or when the fluid transfer device 100 a is at rest.

As discussed above in the context of infusion device 200, thecapacitor(s) are carried on a board along with an RF communicationdevice that is connected to an antenna. The communication device may,alternatively, be an an oscillating magnetic field communication device,a static magnetic field communication device, an optical communicationdevice, an ultrasound communication device, a direct electricalcommunication device, or other suitable device. A controller 534 (FIG.41), such as a microprocessor, microcontroller or other controlcircuitry, is carried on the other side of the board. The controllercontrols the operations of the infusion device 500 in accordance withinstructions stored in memory and/or provided by and external device byway of the aforementioned communication device. For example, thecontroller 534 may be used to control the fluid transfer device 100 a tosupply fluid to the patient in accordance with, for example, a storedbasal delivery schedule or a bolus delivery request, by selectivelyactuating (i.e. opening) and de-actuating (i.e. closing) the activevalves 554 and 556.

Referring to FIGS. 40 and 41, the exemplary infusion device 500 is alsoprovided with a side port 536 that is connected to a passageway betweenthe outlet of the active valve 556 and the outlet port 516. The sideport 536 facilitates access to an implanted catheter 520, typically byway of a hypodermic needle. For example, the side port 536 allowsclinicians to push fluid into the catheter 520 and/or draw fluid fromthe catheter. The outlet port 516, a portion of the associatedpassageway, the antenna and the side port 536 are carried by a headerassembly 538. The header assembly 538 is a molded, plastic structurethat is secured to the housing 502. The housing 502 also includes asmall aperture through which portions of the passageway are connected toone another, and a small aperture through which the antenna is connectedto the board.

The exemplary infusion device 500 may include a pressure sensor 540between the active valve 556 and the outlet port 516. As such, thepressure sensor 540 senses the pressure at the outlet port 516 which, inthe illustrated embodiment, is also the pressure within the catheter520. Another pressure sensor 542 may also be between the reservoir 510and the active valve 554. The pressure sensor 542 may be used to measurethe reservoir pressure. The pressure sensors 540 and 542, which areconnected to the controller 534, may also be used to measure thepressure differential across the fluid transfer device 100 a and toanalyze a variety of aspects of the operation of the exemplary infusiondevice 500. For example, pressure measurements may be used to determinewhether or not there is a complete or partial blockage in the catheter520.

Although the inventions disclosed herein have been described in terms ofthe preferred embodiments above, numerous modifications and/or additionsto the above-described preferred embodiments would be readily apparentto one skilled in the art. By way of example, but not limitation, thepresent inventions have application in infusion devices that includemultiple reservoirs and/or outlets. Moreover, the inventions include anyand all combinations of the elements from the various embodimentsdisclosed in the specification. It is intended that the scope of thepresent inventions extend to all such modifications and/or additions andthat the scope of the present inventions is limited solely by the claimsset forth below.

1. A fluid transfer device for use in an implantable medical device,comprising: a fluid transfer device housing configured to be carriedwithin the implantable medical device; a pump associated with the fluidtransfer device housing; and a valve in fluidic communication with thepump, the valve including a valve housing including a fluid lumen, avalve seat including an opening in fluid communication with the fluidlumen, and a valve element having an end portion that faces the opening,the valve element being movable toward the valve seat and away from thevalve seat between a closed position where the valve element end portionthat faces the opening is aligned with the opening and engages the valveseat and an open position where the valve element end portion that facesthe opening is aligned with the opening and is in spaced relation to thevalve seat, wherein one of the valve seat and the valve element endportion that faces the opening includes a main portion and a sealportion that is less tacky than the main portion and is in contact withthe other of the valve seat and the valve element end portion that facesthe opening when the valve element is in the closed position.
 2. A fluidtransfer device as claimed in claim 1, wherein the valve seat includesthe main portion and the seal portion; the valve element includes ashaft that extends through the valve housing fluid lumen and valve seatopening, and a head that defines the end portion that faces the opening;and the valve further includes a spring that biases the valve element tothe closed position.
 3. A fluid transfer device as claimed in claim 1,wherein the valve is a main check valve that defines the inlet of thefluid transfer device, a bypass valve, or an outlet valve.
 4. A fluidtransfer device as claimed in claim 1, wherein the main portion isformed from an elastomeric material selected from the group consistingof silicone rubber, latex rubber, fluoropolymers, urethane, butylrubber, and isoprene.
 5. A fluid transfer device as claimed in claim 1,wherein the main portion is formed from an elastomeric material; and theseal portion comprises a layer of silicon suboxide on the main portion.6. A fluid transfer device as claimed in claim 1, wherein the mainportion is formed from an elastomeric material; and the seal portioncomprises a relatively thin layer of a relatively hard elastomericmaterial.
 7. A fluid transfer device as claimed in claim 1, wherein themain portion is formed from an elastomeric material; and the sealportion comprises a relatively thin layer of a fluoroelastomer or a lowfriction protective coating.
 8. A fluid transfer device as claimed inclaim 1, wherein the main portion is formed from an elastomericmaterial; and the seal portion comprises a surface of the main portionthat has been halogenated.
 9. A fluid transfer device as claimed inclaim 1, wherein the main portion is formed from an elastomericmaterial; and the seal portion comprises a surface of the main portionthat has been implanted with ions of a ceramic material or ions of ametal material or ions of a metal oxide material.
 10. A fluid transferdevice as claimed in claim 1, wherein the main portion is formed from anelastomeric material; and the seal portion comprises a surface of themain portion that has been implanted and coated with ions of a ceramicmaterial or ions of a metal material or ions of a metal oxide material.11. A fluid transfer device as claimed in claim 1, wherein the mainportion is formed from an elastomeric material; and the seal portioncomprises a coating of a filler material.
 12. A fluid transfer device asclaimed in claim 1, wherein the valve element end portion engages asurface on the valve seat; and the valve element end portion moves in adirection that is perpendicular to the valve seat surface.
 13. A fluidtransfer device for use in an implantable medical device, comprising: afluid transfer device housing configured to be carried within theimplantable medical device; a pump associated with the fluid transferdevice housing; and a valve in fluidic communication with the pump, thevalve including a valve housing including a fluid lumen, a valve seatincluding an opening in fluid communication with the fluid lumen, and avalve element movable relative to the valve housing between a closedposition where the valve element engages the valve seat and an openposition where the valve element is in spaced relation to the valveseat, the valve seat including a main portion and a seal portion that isless tacky than the main portion and is in contact with the valveelement when the valve element is in the closed position.
 14. A fluidtransfer device as claimed in claim 13, wherein the valve seat mainportion is formed from an elastomeric material selected from the groupconsisting of silicone rubber, latex rubber, fluoropolymers, urethane,butyl rubber, and isoprene.
 15. A fluid transfer device as claimed inclaim 13, wherein the valve seat main portion is formed from anelastomeric material; and the valve seat seal portion is selected fromthe group consisting of a layer of silicon suboxide on the main portion,a relatively thin layer of a relatively hard elastomeric material, arelatively thin layer of a fluoroelastomer or a low friction protectivecoating, a surface of the valve seat main portion that has beenhalogenated, a surface of the valve seat main portion that has beenimplanted with ions of a ceramic material or ions of a metal material orions of a metal oxide material, a surface of the valve seat main portionthat has been implanted and coated with ions of a ceramic material orions of a metal material or ions of a metal oxide material, and acoating of a filler material.
 16. A fluid transfer device for use in animplantable medical device, comprising: a fluid transfer device housingconfigured to be carried within the implantable medical device; a pumpassociated with the fluid transfer device housing; and a valve influidic communication with the pump, the valve including a valve housingincluding a fluid lumen, a valve seat including an opening in fluidcommunication with the fluid lumen, and a valve element, including avalve element head, movable relative to the valve housing such that thevalve element head moves toward the valve seat and away from the valveseat between a closed position where the valve element head engages thevalve seat and an open position where the valve element head is inspaced relation to the valve seat, the valve element head including amain portion and a seal portion that is less tacky than the main portionand is in contact with the valve seat when the valve element is in theclosed position.
 17. A fluid transfer device as claimed in claim 16,wherein the valve element main portion is formed from an elastomericmaterial selected from the group consisting of silicone rubber, latexrubber, fluoropolymers, urethane, butyl rubber, and isoprene.
 18. Afluid transfer device as claimed in claim 16, wherein the valve elementmain portion is formed from an elastomeric material; and the valveelement seal portion is selected from the group consisting of a layer ofsilicon suboxide on the main portion, a relatively thin layer of arelatively hard elastomeric material, a relatively thin layer of afluoroelastomer or a low friction protective coating, a surface of thevalve element main portion that has been halogenated, a surface of thevalve element main portion that has been implanted with ions of aceramic material or ions of a metal material or ions of a metal oxidematerial, a surface of the valve element main portion that has beenimplanted and coated with ions of a ceramic material or ions of a metalmaterial or ions of a metal oxide material, and a coating of a fillermaterial.
 19. A fluid transfer device as claimed in claim 16, whereinthe valve element head engages a surface on the valve seat; and thevalve element head moves in a direction that is perpendicular to thevalve seat surface.